In ATM systems errors of various kinds may occur and must all be detected in whatever way. For instance, an error is certainly present when no bit or cell synchronisation can be performed. Also the absence of response to whatever questions should be recognized as an error. It is also known to include in the information part of an ATM cell an error protection code to detect transmission errors.
Not all kinds of errors can be detected. This is the case with errors which occur only spuriously, although such errors adversely affect the transmission quality of an ATM connection between two points of an ATM network.